Traditional corn chip processing includes the batch cooking and soaking in water of whole kernel corn with the addition of calcium hydroxide (lime) in a process that takes 8 to 12 hours. The cooking and soaking or steeping in water softens and hydrates the corn. The cooked and soaked materials is then washed to remove corn pericarp and drained of lime water; ground to produce masa; sheeted; cut into appropriate shapes, e.g., triangles, rounds, etc.; possibly proofed in a direct fire oven; and fried to a final moisture content. The process involves many time consuming and labor intensive steps, as well as producing an alkaline wasted water disposal problem.
More recently, Mapampianti (MAPA), an Italian equipment supplier, has developed an extrusion process which eliminates the husk removal and the alkaline waste water but still requires about six to eight hours of soaking time. Briefly, the MAPA tortilla process requires soaking of whole kernel corn in tap water to rehydrate the corn. The soaked corn is then transferred to a first single screw extruder for procesing with the original soak water. Excess water is returned to the soak tank and remixed with new water for soaking of the next batch. The corn is transferred to another extruder and eventually ground, cooked and sheeted. A substantially similar process is disclosed in U.S. Pat No. 4,778,690 of the Oct. 18, 1988 to MAPAM, INC., which appears to be a MAPA related company.
U.S. Pat. Nos. 4,834,996 of May 30, 1989 to Fazzolare et al and 4,645,679 of Feb. 24, 1987 to Lee et al disclose the manufacture of snack products from corn flour or comminuted corn wherein twin screw extruders are diclosed for some portion of the process.
U.S. Pat. No. 4,769,253 of Sept. 6, 1988 to Willard relates to a process for producing extruded fried snack products which have not been treated with lime from a variety of dry-milled corn ingredients.
U.S. Pat Nos. 3,278,311 of Oct. 11, 1966 to J.D. Brown et al; 4,803,091 of Feb. 7, 1989 to Mottur et al; and 3,020,162 Feb. 6, 1962 to Cunningham, Et Al show conventional methods for making corn chips.
U.S. Pat. No. 4,645,679 of Feb. 24, 1987 to Lee et al shows a generally conventional process for making a corn chip wherein a cooking extruder, preferably a twin screw extruder is used to enhance hydration and gelatinization of the starch.
U.S. Pat. No.4,748,037 of May 31, 1988 to Mastumoto et al as well as its initially filed Japanese patent application 59-178407 of Aug. 29, 1984 relates to a continuous method for preparing a soft snack food cake by extrusion cooking of whole or hulled beans or cereals such as corn in a twin screw extruder.
U.S. Pat Nos. 4,500,588 of Feb. 19, 1985 to Fulger; 3,458,321 July 26, 1969 to Reinhart et al; 4,756,921 of Jul. 12, 1988 to Calandro et al; and 4,790,996 of Dec. 13, 1988 to Roush et al disclosure the processing of various corn products on twin screw extruders.